Shunt valve and method of use

ABSTRACT

An operable shunt valve comprises a housing containing an inlet conduit for receiving fluid, an outlet conduit in fluid communication with the inlet conduit and a valve seat positioned between the inlet and the outlet conduits. A normally closed valve is movably positioned in the housing resting against the valve seat and adapted to move away from the valve seat in response to fluid pressure in the inlet conduit. A normally collapsed expansible balloon is positioned in the inlet conduit and, when expanded, adapted to contact the valve to lift the valve from the valve seat. A reservoir mechanism is provided for controllably and manually expanding the balloon to thereby force the valve open in the event the valve becomes unresponsive to fluid pressure in the inlet. A method of using an operable, implanted shunt valve, substantially as described above, is also within the purview of the present invention.

This is a continuation of application Ser. No. 414,990, filed Sept. 3,1982, now U.S. Pat. No. 4,475,899.

FIELD OF THE INVENTION

The present invention relates to a shunt valve assembly with a clearingmechanism and a method for clearing the shunt valve in the event thevalve becomes unresponsive to fluid pressure, and more particularly,concerns an implantable ascites shunt valve with a clearing mechanismused for transferring ascites fluid from the peritoneal cavity to thevascular system of a patient and a method for clearing the ascites shuntvalve.

DESCRIPTION OF THE PRIOR ART

Certain physiological conditions, such as cirrhosis, cause theaccumulation of ascites fluid in the peritoneal cavity. Continuedaccumulation can cause death. This condition can be relieved bysurgically draining the peritoneal cavity. However, the ascites fluid isrich in protein and loss of these nutrients could lead to malnutrition.

The problems created by ascites fluid accumulation in the peritonealcavity and the surgical relief of this accumulation were recognized byDr. H. H. LeVeen who invented an implantable shunt valve assembly (U.S.Pat. No. 3,910,283) to allow ascites fluid, driven by pressure in theperitoneal cavity, to travel through a one-way valve to the patient'svascular system. The LeVeen invention uses a valve diaphragm whichallows flow of ascites fluid to the vascular system when theintraperitoneal pressure exceeds the central venous pressure by apredetermined amount.

It is also possible that deposits such as precipitate of salts or othersubstances from the ascites fluid may, in time, build up so as to renderthe valve inoperable. This problem was recognized by J. B. Newkirk,patentee of a shunt valve assembly (U.S. Pat. No. 4,240,434) with anasymmetrical one-way duck-bill valve contained in a flexible pump body.U.S. Pat. No. 4,240,434 teaches that the asymmetrical properties of thevalve make it self-cleaning and that squeezing the pump body, which ispositioned such that ascites fluid enters it after leaving the duck-billvalve, further clears the valve. However, the Newkirk apparatus reliesupon fluid pressure built up by squeezing action of the pump, ratherthan direct physical contact to force the valve open. This squeezingaction causes fluid to be forced out of the valve system. When the shuntvalve communicates with the venous system there is a possibility thatblood will clot at the end of the tube in contact with the blood supply.The fluid being forced out of the shunt valve system can potentiallydislodge a blood clot that may have formed at the end of the outlettube, and set it free in the circulatory system where it can potentiallyharm the patient. In addition, Newkirk's design requires that the shuntvalve be placed at the same location as the means for activating theclearing mechanism. There is a risk of crushing or damaging the valve orbreaking cemented joints when applying pressure to a pump body whichcontains the shunt valve. Also, failure of the pump body could lead toblood escaping the venous system.

With the above-mentioned deficiencies in mind it is desired to provide,in particular, an ascites shunt valve with a means and a method forforcing the valve open in the event it becomes unresponsive to thepressures exerted by the ascites fluid. It is desired to provide aclearing mechanism that does not force fluid into the venous systemsince this fluid may dislodge particles on the surface of the outlettube and set them free in the patient's circulatory system. It isfurther desired to provide a clearing mechanism preferably contained ina separate system so that the components of the shunt valve are notexposed to the forces required to activate the clearing mechanism andthat unexpected failure of the clearing mechanism will not result infailure of the integrity of the fluid path of the ascites fluid from theperitoneal cavity to the vascular system. It is also desired to have aclearing mechanism that need not be placed at the same location as theshunt valve.

SUMMARY OF THE INVENTION

The shunt valve of the present invention comprises a housing containinginlet means, outlet means and normally closed valve means responsive tofluid pressure in the inlet means for allowing fluid flow between theinlet means and the outlet means. Externally activated means is providedfor controllably contacting and forcing the valve means into an openposition to assure fluid flow between the inlet means and the outletmeans in the event the valve means is unresponsive to fluid pressure inthe inlet means.

In a preferred embodiment of one aspect of the present invention anoperable implantable ascites shunt valve includes a housing whichcontains an inlet conduit for receiving ascites fluid from theperitoneal cavity of the patient and an outlet conduit in fluidcommunication with the inlet conduit for delivering ascites fluid intothe vascular system of the patient. A valve seat is positionedintermediate the inlet conduit and the outlet conduit, and a normallyclosed valve diaphragm is movably positioned in the housing restingagainst the valve seat. The valve diaphragm is adapted to move away fromthe valve seat in response to fluid pressure in the inlet conduit toallow ascites fluid flow between the inlet conduit and the outletconduit. A normally collapsed expansible balloon is positioned in theinlet conduit. When the balloon is expanded it occludes the inletconduit thus preventing ascites fluid from reaching the valve diaphragm;further it contacts the valve diaphragm to lift it from the valve seat.A flexible tube is connected at one end to, and is in fluidcommunication with, the balloon. The tube exits the housing through afluid-tight orifice in the inlet conduit and is connected at its otherend to a flexible, normally expanded reservoir. A quantity of fluidfills the volume described by, and is transferable among, the reservoir,tube and balloon. When the reservoir is implanted in the patient it issubcutaneously accessible to the patient. In the event that the valvediaphragm is unresponsive to fluid pressure in the inlet conduit thepatient may restore fluid flow between the inlet conduit and the outletconduit by compressing the reservoir with sufficient force to collapsethe reservoir and expand the balloon whereby the balloon in its expandedposition occludes the inlet conduit and lifts the valve diaphram fromthe valve seat.

Another aspect of the present invention is a method of clearing a valveimplanted in an animal body. The implanted valve has a housingcontaining inlet means, outlet means and normally closed valve meansresponsive to fluid pressure in the inlet means, and includescontrollable clearing means for contacting and forcing the valve meansinto an open position. In accordance with the invention, the methodcomprises activating the clearing means in the event that the valvemeans is unresponsive to fluid pressure in the inlet means therebyrestoring fluid flow between the inlet means and the outlet means.

In accordance with the principles of the present invention a number ofadvantages and objectives are achieved. Primarily, the present inventionprovides an ascites shunt valve with a clearing mechanism for forcingthe valve open in the event it becomes unresponsive to the pressuresexerted by the ascites fluid. The present invention provides a clearingmechanism that does not force fluid through the shunt valve system whereit can dislodge particles on the surface of the outlet tube and set themfree in the patient's circulatory system. The present invention alsoprovides a clearing mechanism that is preferably contained in a separatesystem from the shunt valve system that transports the ascites fluidfrom the peritoneal cavity to the vascular system. Therefore, thepresent invention offers the advantage of protecting the preferred valvediaphragm from the forces used to activate the clearing mechanism evenif the housing and the reservoir are in close proximity to each other. Afurther advantage provided by the separate systems of the presentinvention is that uxexpected failure of the balloon, tube or reservoirwill not allow ascites fluid or blood to escape from the system.Finally, the present invention allows positioning of the reservoir in adifferent location from the shunt valve. This may be done in order tooptimize the flow path of the ascites fluid or to accommodate specialsituations regarding the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of the preferred implantable ascitesshunt valve of the present invention;

FIG. 2 is a top elevational view of the preferred implantable ascitesshunt valve of the present invention;

FIG. 3 is an enlarged cross-sectional view of the ascites shunt valve ofFIG. 2 along line 3--3 illustrated without inlet and outlet tubes andshowing the balloon in its normally collapsed position;

FIG. 4 is an enlarged cross-sectional view of the ascites shunt valve ofFIG. 2 illustrated without inlet and outlet tubes and showing theballoon in the expanded position;

FIG. 5 is an enlarged top elevation view of the valve diaphragm;

FIG. 6 is a perspective view showing the reservoir attached to the lowerportion of the patient's rib cage;

FIG. 7 is a perspective view showing the patient applying digitalpressure to compress the reservoir mounted to the lower portion of thepatient's rib cage;

FIG. 8 is an enlarged cross-sectional view of an alternative embodimentof the ascites shunt valve of the present invention; and

FIG. 9 is a side elevational view of an alternative embodiment of theascites shunt valve of the present invention.

DETAILED DESCRIPTION

While this invention is satisfied by embodiments in many differentforms, there is shown in the drawings and will herein be described indetail preferred embodiments of the invention with the understandingthat the present disclosure is to be considered as exemplary of theprinciples of the invention and is not intended to limit the inventionto the embodiments illustrated. The scope of the invention will bemeasured by the appended claims and their equivalents.

Turning to FIGS. 1 through 5, an operable ascites shunt valve assembly10 includes a housing 11 with an upper portion 12 and a lower portion 14and a cavity 13 formed by the upper and lower portions. The housingcontains an inlet conduit 15 preferably for receiving ascites fluid fromthe peritoneal cavity and an outlet conduit 16 in fluid communicationwith the inlet conduit. A circular valve seat 17 is located in the fluidpath between the inlet and outlet conduits. In the embodiment shown, theinlet conduit has an angular displacement with respect to the outletconduit. However, it is within the purview of this invention that theexterior of the housing can assume a variety of shapes and that theangles, if any, of the inlet and the outlet conduits relative to eachother and to the housing can vary to accommodate different possibleimplant locations of the housing.

A flexible inlet tube 19 preferably with perforations 20, is connectedto the inlet conduit and a flexible outlet tube 21 is connected to theoutlet conduit. When implanted in the human body, inlet tube 19communicates with the peritoneum. Perforations 20 facilitate entry ofascites fluid into the inlet tube. Outlet tube 21 is inserted into alarge jugular vein or other large vein for passage of fluid into thevascular system.

A normally closed valve diaphragm 22 is movably positioned in thehousing and rests against circular valve seat 17. In the preferredembodiment the valve diaphragm consists of an inverted cup-shapedsealing skirt 24 sized and shaped to fit the circular valve seat, acentral connecting member 25 which is located between the sealing skirtand four radial struts 26 and peripheral support ring 27 connected tothe radial struts. The peripheral support ring is positioned in acircular positioning slot 29 in the lower portion of the housing and itis held in this position by six locking lugs 30 which are an integralpart of the upper portion of the housing. Valve diaphragm 22 is adaptedto move away from the valve seat in response to fluid pressure in theinlet conduit to allow fluid flow from the open valve through spaces 31,between radial struts 26, and to the outlet conduit. When the pressureof the ascites fluid in the peritoneum exceeds the central venouspressure by a predetermined amount the valve diaphragm is forced openand ascites fluid flows through the housing to the vascular system. Itis preferred that the valve diaphragm open when the ascites fluidpressure is approximately 3 cm H₂ O greater than the central venuspressures. A description of the shunt valve thus far is similar to thatfound in U.S. Pat. No. 3,910,283.

A normally collapsed expansible balloon 32 is positioned in an expandedportion 34 of the inlet conduit. The balloon is designed such that, whenexpanded, it preferably occludes the inlet conduit preventing furtherascites fluid from reaching the valve diaphragm, and it contacts thevalve diaphragm to lift same from valve seat 17. A flexible tube 35 isconnected at one end and is in fluid communication with the balloon.Tube 35 exits the lower portion of the housing through a fluid tightorifice 36. In the preferred embodiment, an adhesive is used tocompletely seal orifice 36 after tube 35 is positioned in the orificeand to secure tube 35 so that it cannot move relative to orifice 36. Theposition of orifice 36 and the length of tube 35 positioned in expandedportion 34 should be chosen to position the balloon approximately asshown in FIG. 3. The other end of tube 35 is connected to and is influid communication with a normally expanded flexible reservoir 37. Thereservoir when expanded preferably has an interior volume that is largerthan the interior volume of the balloon when the balloon is expanded. Aquantity of fluid fills the volume described by the balloon, tube andreservoir whereby compression of the reservoir is adapted to expand theballoon due to the transfer of fluid from the reservoir, through thetube and to the balloon.

Turning now to FIGS. 6 and 7, reservoir 29 is implanted in the patient Psuch that it is subcutaneously accessible. One possible area forimplanting the reservoir would be adjacent to the rib cage 50 since theribs provide a firm backing to maintain the position of the reservoirwhen finger pressure is applied to it. If sutures are used to positionthe reservoir it is desirable to provide additional material 39 whichcan be an integral part of reservoir 37 or a separate sheet of materialsuch as polyester reinforced plastic or silicone rubber which is mountedon the reservoir. Although sutures may puncture or damage reservoir 37,additional material 39 can be sutured to the patient to fixedly containthe reservoir in the desired location.

The present invention, as illustrated in the drawings, provides a methodfor clearing an implanted ascites shunt valve. In use, the ascites shuntvalve assembly is implanted in the patient such that inlet tube 19communicates with the peritoneal cavity, outlet tube 20 is inserted intoa large jugular vein or other large vein and reservoir 37 is positionedto be subcutaneously accessible, as shown in FIG. 6. In the event thatthe valve diaphragm becomes unresponsive to ascites fluid pressure inthe inlet conduit, fluid flow between the inlet conduit and the outletconduit may be restored by compressing reservoir 37, as shown in FIG. 7,with sufficient externally applied manual pressure to collapse thereservoir and expand balloon 32 whereby the balloon in its expandedposition occludes the inlet conduit and contacts valve diaphragm 22 tolift same from valve seat 17. The pressure on the reservoir is thenreleased thereby allowing the fluid to return from the balloon to thereservoir; thus the reservoir and the balloon expand and collapse,respectively, to their original positions.

FIG. 8 shows an alternative embodiment of the present invention. Thisembodiment is similar to the previously described embodiment except thata normally collapsed balloon 44, shown expanded, is held in position bya transverse support member 45 positioned in an inlet conduit 46. Theballoon is designed such that, when expanded, it contacts a normallyclosed valve diaphragm 22a and lifts the valve diaphragm from a valveseat 49. It is preferred that balloon 44 be held in an aperture 47 inthe transverse support member by the use of adhesive. The transversesupport member may be a separate member attached to the interior surfaceof the inlet conduit or it may be an integral part of the housing. Itshould be noted that it is within the purview of this invention for theballoon or other like expansible members to be expanded to lift thevalve diaphragm from the valve seat through the use of mechanical forcerather than fluid pressure. This mechanical force may be provided, forinstance, by the use of a flexible guide wire contained within aflexible tube. A balloon or a bellows enclosure may be connected to eachend of the flexible tube and guide wire assembly such that force exertedon one flexible enclosure will force the guide wire along the closelyfitting flexible tube causing the second flexible enclosure inside thehousing to expand and lift the valve diaphragm from the valve seat.Other modifications of the embodiments as described herein are clearlywithin the scope of and spirit of the instant invention.

FIG. 9 shows an alternative embodiment wherein a reservoir 40 isconnected to housing 11a. A tube 41 is connected to and in fluidcommunication with reservoir 40 at one end and is connected to and influid communication with the balloon (not shown) at the other end. Inthis embodiment when the reservoir is compressed to activate theclearing mechanism it is compressed against the housing rather thanagainst a part of the patient's anatomy. The shunt valve of thisembodiment must also be mounted in the patient so that the reservoir issubcutaneously accessible to external digital manipulation. Additionalmaterial, such as polyester reinforced plastic or silicone rubber may beconnected to the housing to provide structure to suture the shunt valvein the desired position in the patient's body. It should be pointed outthat even in this alternative embodiment the present invention offersthe advantage that the valve diaphragm is protected from the manualforce used to activate the clearing mechanism.

Although inlet tube 19 and outlet tube 21 may be made of many differentmaterials, medical grade silicone rubber is preferred. Balloon 32, tube35, reservoir 37 and valve diaphragm 22 are preferably made of medicalgrade silicone rubber. It is preferred that upper portion 12 and lowerportion 14 of the housing be made of a rigid plastic, such aspolypropylene. The upper and lower housing portions are preferably heldtogether with an adhesive suitable for the type of plastic chosen or byusing an ultrasonic welding process. Tube 35 may be connected at one endto balloon 32 and at the other end to reservoir 37 with adhesive. Also,adhesive may be used to position tube 35 in orifice 36 and to seal thisconnection. Silicone oil is the preferred fluid for filling the volumedescribed by the balloon, tube and reservoir. Since the ascites shuntvalve of this invention is preferably sterile when implanted in thepatient all materials should be chosen to accommodate the sterilizationprocess.

Thus, there has been provided in accordance with the present inventionan ascites shunt, or like, valve with a clearing mechanism for forcingthe valve diaphragm open in the event it becomes unresponsive to thepressures exerted by fluid in the inlet.

What is claimed is:
 1. An operable implantable ascites shunt valvecomprising:a housing containing a valve seat, inlet means for receivingascites fluid from the peritoneal cavity and outlet means; normallyclosed valve means movably positioned in said housing resting againstsaid valve seat and responsive to fluid pressure in said inlet means forallowing fluid flow between said inlet means and said outlet means; andmanually activatable means for controllably contacting and forcing saidvalve means from said valve seat into an open position to assure fluidflow between said inlet means and said outlet means in the event saidvalve means is unresponsive to fluid pressure in said inlet means, saidmanually activatable means allowing manual activation at a locationremoved from said housing.
 2. A method of clearing an ascites shuntvalve, implanted in an animal body, of the type having a housingcontaining a valve seat, inlet means for receiving ascites fluid fromthe peritoneal cavity, outlet means and normally closed valve meansmovably positioned in said housing resting against said valve seat andresponsive to fluid pressure in the inlet means for allowing fluid flowbetween the inlet means and the outlet means, the valve includingcontrollable clearing means, manually activatable at a location removedfrom said housing, for contacting and forcing the valve means from saidvalve seat into an open position comprising:manipulatively activatingthe clearing means in the event that the valve means is unresponsive tofluid pressure in the inlet means thereby restoring fluid flow betweenthe inlet means and the outlet means.